1. Field of the Invention
The invention discloses a method and apparatus for electronic distribution of small accurately metered amounts of materials which can control behavior of insects and pests for the benefit of mankind.
2. Background of Related Art
Pheromone dispensing is being widely studied as a means to control pests and has been used in orchards and other agricultural environments for this purpose. Control of pathogenic pests that attack crops, forests, people, pets, and livestock is a monumental universally important task. Blanket spraying of toxic pesticides has caused environmental damage, which is now just beginning to be halted or reversed because of dangers and unanticipated consequences. Biotechnology is being employed in emerging xe2x80x9cgreenxe2x80x9d methods of pathogen control with discrete, precisely timed and monitored application of substances for control. Continued precision targeting of natural chemicals or chemical which mimic natural chemicals will be the key to a minimally-disruptive pest control system. The ultimate version of this approach is the use of insect pheromones, of which a mere few hundred molecules can suffice to lure pathogenic organisms into traps or away from target crops. Disruption of mating can reduce or even eliminate the next generation of insect pests. Pheromones can also be used to lure predatory and beneficial insects into a field for crop protection. These non-toxic environmentally safe developments promise an exciting new era in crop protection.
Most of the common damaging insects, such as the codling moth, do their damage in the adult stage after mating. They penetrate developing fruit in large numbers to lay eggs which develop into larva which produce unsalable product at harvest time. Emergence of the adults is sometimes referred to as the biofix point which is usually based upon a certain number of degree days. The female moths emerge in different orchards, as many as four or five days apart. Females release pheromones which form a plume in wind that spreads and dilutes as it flows downstream. Females may harbor up to a picogram of pheromone when active, according to some researchers. Males have species-specific binding proteins which detect these pheromones and lead to mate seeking activity. It has been reported that males initiate upwind direct flight or xe2x80x9czig zagxe2x80x9d flight in an attempt to reach the source of the sensory sensation. It is known that insect flight for mating occurs mainly in the dusk-to-dawn period and not during daylight hours. Cost effective control has been reported on a commercial scale despite the very high cost of pheromones which are sometimes referred to as semiochemicals. A discussion of semiochemicals and a specific delivery system is found in U.S. Pat. No. 5,645,844, incorporated herein by reference.
Presently, pheromones are dispensed by xe2x80x9cdumbxe2x80x9d, generally xe2x80x9cpassivexe2x80x9d systems that provide no control over timing or amount of pheromone dispensed. Typical dispensing systems are passive xe2x80x9cwickxe2x80x9d type devices or slowly evaporating mixtures of pheromones and matrix from which the pheromone is passively volatilized into the air at a relatively steady but decreasing state until depleted. Some examples of this approach include PVC/twine dispensers, novel sesquiterpene epoxides for embedding volatiles, cuticular waxes, polymeric laminated flakes (Hercon), polymer impregnated time-released dispensers, and others mentioned in the aforesaid patent reference. Some specific examples of commercial dispensing systems are known by the following names are: Sentry, Heliothis, IPS Unitrap, Multipher I, and Hartstack Wiretrap.
Such devices rely upon such processes as diffusion, breaking down of chemical bonds or degradation processes, with volatility as the only mechanism to control the amount or timing of pheromone releases. The rate at which these processes operate is usually temperature dependent. They speed up during the day when actually no usefulness is obtained with respect to night flying insects, and slow down at night when they are most needed. Once such devices are set out, there is no way to control or stop the dispersion of expensive chemicals. More pheromone is needed initially to account for natural decreases which occur as chemicals are depleted with time.
An intermittent spray of material has been proposed as described in U.S. Pat. No. 5,205,064. This device amounts to an aerosol can with an electrically operated cam which operates a lever to open a valve. Some have referred to such devices as an aerosol xe2x80x9cpufferxe2x80x9d. The pressurized aerosol dispenser has a mechanically actuated push valve. Puffer devices are fairly large and also influenced by temperature. They require a propellant which may not be compatible with some pheromones. They are subject to clogging and canister failure problems. Puffer devices do enable the use of a timer to permit dispensing during the desired period and not dispensing during other periods. Droplet size control is nearly nonexistent with a wide variety of drop sizes produced. The output may vary as internal pressure in the canister drops during use. There is also a piezoelectric xe2x80x9cbuzzerxe2x80x9d that is used to assist in the dispersement of the pheromone material into the air.
Substances to be dispensed will include pheromones, semiochemicals, and any other chemicals which have usefulness for the control of pest behavior. These materials can be synthesized from the constituent amino acids in the case of peptide pheromones and purchased from a relatively large number of commercial pheromone producers such as Ciba Geigy, Concep, Hercon and Ecogen for instance. There are three fundamental ways pheromones and related chemicals are typically used for pest control, although additional ways are not precluded.
One way pheromones are used is to lure pests to traps for simple killing or for trapping for subsequent counting. The puffer device shown in U.S. Pat. No. 5,205,064 employs an electrified grid which electrocutes the insects when they try to reach the source of attractant. Counting the number of a particular species of insect is important in determining the level of infestation as well as identifying the biofix time. The attract-and-kill method and the attract-trap-count technique both use pheromones the will attract an insect species. The most straight forward version of this approach is, for example, the use of a female insects sex lure to attract conspecific males for trapping, killing or counting. In this case, the pheromone would be naturally occurring scent materials either harvested from the females or synthesized as exact replicas of the naturally-occurring pheromone.
A second way pheromones can be used for crop protection is to dispense pheromones or seriochemicals that will lure predators to the field which naturally attack and kill pests for which control is sought.
A third approach for pest control through use of pheromones is called the xe2x80x9cdisruptionxe2x80x9d approach briefly mentioned above. Pheromones which will disrupt mating or maturation of the pest in the field are dispensed, thus stopping the production of pests that are attacking the crop. If a female sex lure causes all of the males to mate or seek to mate with the pheromone dispenser instead of mating with real females, the breeding cycle will be disrupted and real mating will not occur. In all of these cases, optimum control of these pests would be obtained by dispensing minute amounts (pico- or nano-liter volumes) of the controlling pheromone or semiochemical in an intermittent pattern that is optimally interactive with time of day, time of year and other climactic and environmental conditions.
The invention comprises an improved apparatus and method for controlled xe2x80x9cjettingxe2x80x9d of pheromones xe2x80x9con demandxe2x80x9d at the highest useful concentration at precisely the times and places that will maximally disrupt mating. It is useful for improved efficiency and control in the other pest control methods as well. The invention is a xe2x80x9csmartxe2x80x9d system which will dispense pheromones in a discrete, micro-drop-by-micro-drop fashion, as required, under direct digital control. It is the application of controlled ink jet technology to dramatically increase effectiveness of these non-toxic pest control methods. Electronically actuated dispensers are provided having an ejection device with an orifice in fluid communication with a fluid reservoir containing a pest specific volatile fluid in the reservoir. A unique coiled tube reservoir is disclosed.
The fluid is selected to predictably alter the physiology or behavior of pests.
Although the main use of this invention is expected to be the attraction or modification of behavior of insects that are detrimental to plants, it should be understood that the pheromone distribution system and apparatus could be used to attract beneficial insects such as pollinators or even to attract predators of insects which are harmful to plants. The term xe2x80x9cpestsxe2x80x9d as used herein, should be construed with these additional connotations in mind.
The electronically actuated ejection device is selected from the group consisting of piezoelectric, magnetorestrictive, inductive, thermal and fast solenoid valve dispensing devices. The dispensing devices are configured to eject a series of uniform individual micro-droplets within a range of diameters between about 2 to about 500 microns. These may be referred to herein as Agjets. Agjets in the preferred embodiment employ solid state piezoelectric dispensing jets. The Agjet dispensers can dispense individual droplets of pheromone as small as 20 trillionths of a liter in size. Agjets can dispense 20 picoliter (pl) or larger droplets at rates from 1 to 5,000 drops per second, for precise controlled dispensing. Requiring only trivial amounts of power to dispense, Agjets can be battery- or solar-powered and triggered by remote radio-control.
Agjet control systems can generate any arbitrary pattern of pheromone delivery that would be optimum for control of pests. Moreover, by broadcasting weather conditions and other data to a central control station, Agjets equipped with sensors and transceivers can inform central processing systems when the optimum conditions for dispensing can or cannot be obtained. A control unit is used to actuate the dispenser during a selected time interval or intervals to produce successive individual micro-droplets of a selected uniform size within a desired range of droplet sizes. The Agjet dispenser is operated through the control unit. Droplets of a selected uniform size within the desired range of diameters are ejected from the orifice at a rate sufficient to release a desired amount of the volatile material from the reservoir over a selected time interval at a uniform rate in order to control pests. Although Agjet dispensers may deposit the ejected micro-droplets onto a wick for more efficient volatilization, it is the digital control of the device which is important.
The Agjet dispensing apparatus is comprised of one or more of the following components: (a) one or a plurality of reservoirs to hold pheromones or other behavior-modifying chemicals in volumes ranting from 1 ul to 100 ml. (b) chemical additives including but not limited to antioxidants that extend the life-span of stored pheromones or other chemicals in the reservoirs (c) one or a plurality of fluid conduits providing a means to convey fluids from said reservoirs to one or a plurality of dispensing devices (d) one or a plurality of electronically-actuated dispensing devices providing a means to dispense into the air drops of fluid ranging in size from 2 um to 500 um in diameter (e) a controlling electronic circuit providing a means to dispense one or more drops from one or more of the dispensing devices at rates from 0 to 4,000 drops per second (f) a means to convey or store electronic charge for the purpose of powering the electronic control circuit (g) an electromagnetic signal receiver providing a means for electromagnetic signals (e.g., laser, radio, microwave) to control the dispensing of drops (h) solar-cells for charging batteries or directly driving the electronic circuitry (i) apparatus providing a means to measure variables such as wind speed, wind direction, humidity, ambient temperature, ambient light, (j) an apparatus providing the means to broadcast the data mentioned in xe2x80x9cixe2x80x9d to receiving equipment by any of the mechanisms described in xe2x80x9cgxe2x80x9d. Agjet dispensers can be dispersed within a field or greenhouse with or without environmental condition sensors and hard wired into a programmed controller or equipped with what may be referred to as xe2x80x9ctransceiversxe2x80x9d which operate on an electromagnetic frequency signal sent to or received from a remote programmed controller in a central processing system. Orchards, vineyards and greenhouses are well suited for a permanent or semi-permanent installation of dispersed pheromone dispensers. In row crops, dispensers mounted on stakes are installed after planting and removed before harvest.
An interactive real time system of dispersed dispensers is equipped with electromagnetically-activated receivers and driving circuits which operate the dispensers. A remote electromagnetic transceiver and programmed digital computing device connected to the transceiver comprises a remote control unit. One or more environmental monitoring stations which communicates with a transceiver is capable of monitoring an environmental condition parameter and transmitting a signal representative of the condition to the remote control unit or even to individual Agjet dispensers that are equipped with receivers and appropriate control circuits. For example, sensing of excessive wind speed during a timed dispensing cycle could result in a signal being sent to the individual Agjet dispensers to cease dispensing. At some intermediate wind speed, a signal could be sent to increase the amount of pheromone material dispensed by increasing the frequency of electrical pulses being delivered to the dispensing unit. The preferred system uses a master control station which communicates with the environmental station and then the master control station sends signals to control the individual dispensers.
Compared to passive xe2x80x9cwickxe2x80x9d style pheromone delivery systems, radio-controlled Agjets can provide the following advantages: (a) optimizing timing of pheromone releases to accomplish the desired pest control objective with smaller amounts of expensive pheromone; (b) the inventive dispensers dispense from a sealed reservoir which allows long term operation (a year or more) without the need for replenishing the pheromone; (c) precise control of drop size and rate of drop production permits precisely controlled dispensing which saves expensive pheromones and allows instantaneous adjustment of the amount of pheromone dispensed or cessation of dispensing in response to the condition of environmental parameters; (d) a control system, such as radio-control, which permits interactive dispensing with respect to season, crop status, weather (wind speed and direction, humidity, temperature), presence of pests or predators, etc. and (e) interactive dispensing through use of a control system allows geographically-staggered units to be activated in sequence, thus xe2x80x9cleadingxe2x80x9d insects in a desired direction.
In addition to these advantages as compared to existing xe2x80x9cpufferxe2x80x9d technology employing mechanical activation of pressurized aerosol spray cans, the ink-jet style miniature dispensers referred to as Agjets offer advantages in the following respects: (a) there are no pressurized containers to maintain or replace; (b) the Agjet package even including a transceiver is a much smaller package for storing, dispensing and controlling dispensing as compared to aerosol spray can systems which is on the order of {fraction (1/20)}th the overall size of the package; (c) electronically controlled individual dispensers, such as piezoelectric dispensers, operate in response to an electrical pulse which does not have the reliability problem of mechanical actuators; (d) there are no environmentally-threatening propellants necessary or problems associated with compatibility between propellants and sensitive pheromones; (e) although the preferred piezoelectric dispensers move slightly with each electrical pulse to disperse individual droplets, the movement is a bulk material movement and does not involve any mechanical moving parts.